Electric knife sharpener



1959 w. H. BODLE 2,897,637

ELECTRIC KNIFE SHARPENER Filed Jan. 15, 1958 2 Sheets-Sheet 1 z E! (9/1I 11 i 4 5 iii i M722 1 24 7152121? E ,HODLE,

INVENTOR.

Aug. 4, 1959 i w. H. BODLE 2,397,537

ELECTRIC KNIFE SHARPENER Filed Jan. '15, 1958 7 2 Sheets-Sheet 2 .haurseE 80045,

' INVENTOR.

ELECTRKC KNIFE SHARPENER Application January 15, 1958, Serial No.709,146

4 Claims. (Cl. 51--128) This invention relates to improved electricallyoperated knife sharpening devices, typically usable as kitchenappliances in the home, and which may if desired be utilized m me typeof combined knife sharpening and can opening device disclosed in mycopending application Serial Number 626,114, filed December 4, 1956, onCan Opening and Knife Sharpening Device. The present application is acontinuation-in-part of that prior application.

A device embodying the invention includes an electric motor, and agrinding wheel driven by the motor at a speed to properly sharpen aknife blade which is placed in contact with the wheel. The motor and atleast a portion of the grinding wheel are contained within a housingwhich is so constructed as to allow proper sharpening contact of thewheel with the knife blade.

The general object of the present invention is to provide an improvedsharpener of this type which is especially designed to allow very quickand easy removal and replacement of the grinding wheel assembly after ithas become worn. In prior home-use sharpeners of this general type, themethod of mounting of the grinding wheel has generally been such as torequire returning of the entire device to the factory or service stationwhen it becomes necessary to remove and replace the grinding-wheel. In adevice embodying the present invention, on the other hand, the grindingwheel and its shaft may be very easily removed, and a new wheelsubstituted, in the home and without special tools or equipment of anytype.

To achieve this ease of replacement, I provide the housing of the devicewith a cover section which is removable to allow access to the grindingwheel, and I so design the mounting for the grinding wheel as to causethe cover section of the housing to itself lock the grinding wheel inits active grinding position, when the cover is in place on the housing.As a result, the grinding wheel may be very easily freed for removalfrom the housing merely by detachment of the cover from the housing.Preferably, the cover performs this function by engaging and locking ahearing or bushing in place, which bearing acts to journal the grindingwheel for rotation about a predetermined axis. This bushing may journalone end of a shaft which carries the grinding wheel, with a secondbushing being provided for journalling the opposite end. Also, thatshaft may carry a gear which is engageable with an associated drivinggear when the shaft is in its active position, to thus transmit drivingpower from the motor to the grinding wheel.

The cover section preferably is apertured to pass a knife blade intocontact with the grinding wheel, and also desirably carries guide meansfor holding the blade in an optimum position during the sharpeningoperation. Certain particular features of the invention have to do witha preferred construction for the cover, according to which the cover mayhave two converging slots for receiving and guiding a knife blade, withthese slots being formed in unique manner by two separately formed partswhich form together a composite cover assembly.

The above and other features and objects of the present invention willbe better understood from the following detailed description of thetypical embodiment illustrated in the accompanying drawings in which:

Fig. 1 is a perspective view of a combination can opener and knifesharpener device constructed in accordance with the invention;

Fig. 2 is a front view, partially broken away, of the Fig. 1 device, andtaken on line 22 of Fig. 1;

Fig. 3 is a fragmentary top plan view of the knife sharpener portion ofthe device, and taken on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary vertical section taken on line 44 of Fig. 2;

Figure 5 is an enlarged fragmentary vertical section taken on line 55 ofFig. 2;

Fig. 6 is an enlarged fragmentary vertical section taken on line 66 ofFig. 2.

Fig. 7 is an exploded perspective View of the grinding wheel and itsassociated gears and other parts;

Fig. 8 is an exploded perspective view of the cover assembly whichencloses the upper side of the knife sharpening portion of the device;

Fig. 9 is a fragmentary horizontal section taken on line 99 of Fig. 2;and

Fig. 10 is a View representing the manner in which a new grinding wheelassembly is inserted into operative position in the device.

Referring first to Figs. 1 and 2, and particularly to Fig. 1, I haveshown at 11) a combined can opening and knife sharpening device, whoseknife sharpening portion is constructed in accordance with the presentinvention. This device includes a housing 11, carrying at one of itssides the can opening mechanism generally represented at 12, andcontaining toward its other side (at its right end as seen in Fig. 2) arotary grinding wheel 13 which is accessible to a knife through a pairof elongated slots 14 and 15, in order to sharpen the knife. The canopening mechanism 12 and the grinding wheel 13 are both driven by anelectric motor 16 contained within housing 11. This motor 16 may be aconventional shaded pole induction motor, whose laminated stator isrepresented at 17, and Whose field coil is represented at 18. The rotorof motor 16 is carried by and drives a rotary shaft 19 which turns abouta horizontal axis represented at 20.

Housing 11 may be formed of several cast metal sections, including afirst body section 21, a second section 22 for carrying the can openermechanism 12, and a removable cover assembly 23 which extends over andencloses the upper side of grinding wheel 13. This cover assembly 23 maybe formed of two cast metal sections 24 and 25 rigidly secured together(see Fig. 9). Housing section 22 closes one side of section 21, and issuitably secured thereto, as by screws 24.

The specific details of the can opening mechanism 12 comprise no part ofthe present invention, and therefore this mechanism will not bediscussed in detail in the present application. A more specificdescription of the can opening mechanism will be found in my copendingapplication Serial No. 626,114, filed December 4, 1956, on Can Openingand Knife Sharpening Device. For present purposes, it may be stated thatthe can opening mechanism 12 includes a can advancing wheel 25 driven bymotor 16, through a speed reduction gear assembly, and a cutter wheel 26which is shiftable between can cutting and released positions, and whichwill function to cut a can lid as the can is turned by wheel 25. Cutter26 is shifted by swinging movement of a lever 27 between the uprightinactive position of Fig. 1, and the full line active position of thatfigure. At the end of this swinging movement, lever 27 engages andactuates the movable actuating element 28 of a switch 29 which iscontained within housing 11, and which acts to close the energisingcircuit to motor 16 when switch 28 is so actuated. Lever or handle 27swings about a horizontal axis 29, and is mounted for such swingingmovement by reception of a cylindrical projection 30 of handle 29 withina cylindrical bushing or opening 31 formed in housing part 22.

The stator 17 of electric motor 16 is rigidly mounted in fixed positionwithin housing 11, as by a pair of screws 32 which may extend throughstator 17 and connect into a pair of rigid mounting posts 33 attached tosection 22 of housing 11. Rotor shaft 19 and the carried rotor aremounted for rotation about horizontal axis 20 by means of a pair ofbearings 34 and 35 suitably attached to stator 17. Wheel 25 of the canopening mechanism may be driven by motor 16 through any suitable type ofdrive connection, preferably including a gear train contained within a:gear housing 36 mounted within main housing 11 of the device. Theunderside of housing section 21 may be'closed by a horizontal plate 37,and the entire housing may be supported on a suitable table or othersupport surface 38 by means of a number of rubber feet or cushions 39.

Referring now to Figs. 7 and 9, the motor bearing 35 may be a ballbearing assembly rigidly attached to the inner side of a bracket 40which is in turn rigidly secured to motor stator 17 by means of a pairof screws 41, which pass through a pair of openings 142 in stator 17,and whose ends are screwed into threaded openings 42 in bracket 40. Atthe opposite side of the stator, screws 41 may have heads 43 serving tosecure a second bearing assembly 34 to the stator. The housing bearingassembly 35 may be attached to bracket 40 by means of a pair of ears 45formed on the bearing housing, and containing openings through which apair of lugs 46 on bracket 40 project, with these lugs being upset orpeened to retain the bearing against bracket 40.

Beyond bearing 35, the motor shaft 19 projects through an opening 47 inbracket 40, and rigidly carries at the outer side of this bracket a gear48. This gear may be a die cast type of gear, which is rigidly carriedby and keyed to the shaft. At a location offset forwardly and downwardlyfrom shaft 19, bracket 40 has a short shaft portion 49 cast integrallywith the bracket, and externally cylindrical to rotatably mountthereabout a compound gear 50, which is desirably formed of nylon orother resinous plastic material. The gear 50 is retained against axialdisplacement from about shaft 49 by means of a screw 51 (see Fig. 2),whose shank threadedly connects into an inner threaded recess in shaft49, and whose head is large enough to engage the outer side of gear 50and retain it on the shaft. The gear 50' has a first set of teeth 52which mesh with the teeth of motor driven gear 48, to be driven thereby,and the gear 50 also has a second increased diameter series of teeth 53for meshing with and driving the teeth 54 formed on a preferably castmetal part 55 which carries the :grinding wheel 13. The rotary axes 56and 57 of parts 50 and 55 extend parallel to the horizontal main axis 20of motor 16 and its driven shaft 19. As seen best in Fig. 6, axis 57 ofthe part or shaft 55 is offset to the left of and slightly above themain axis 20. The number of teeth on gears 48, 52, 53 and 54 maytypically be 14 teeth, 14 teeth, 25 teeth, and teeth respectively, sothat the grinding shaft 55 will turn at a speed two and a half times asgreat as the speed of motor shaft 19.

At its opposite ends, the part 55 has a pair of aligned externallycylindrical bearing surfaces or portions 59 and 60, which are receivedand rotatably journaled within a pair of essentially tubular bushingsleeves 61 and 62. These bushings 61 and 62 are desirably formed ofnylon or other suitable long wearing resinous plastic material, to thuseffectively journal the cast metal part 55 with a of wear.

Sleeve 61 is removably receivable 4 within a tubular mounting lug 63formed integrally with and projecting horizontally from bracket 40. Attwo diametrically opposite locations, bearing sleeve 61 may have a pairof small projections 64 which are receivable within notches 65 in lug63, to key part 61 against rotation relative to lug 63. As best seen inFig. 5, the second nylon bushing 62 is preferably made of noncircular(desirably square) cross section, taken in a vertical plane, and has itslower portion partially received and confined within a correspondinglynon-circular recess 66 formed in a portion 67 of housing section 21.More specifically, the recess 66 has a horizontal bottom wall 68 uponwhich a correspondingly horizontal undersurface of part 62 rests, withthe opposite sides of the part 62 being engaged and confined by a pairof vertical walls 69 of recess 66. As will be discussed at a laterpoint, the cover 23 of housing 11 functions to hold the hearing orbushing 62 in fixed position within the housing, when the cover issecured in its position of use.

The grinding wheel 13 is formed of a suitable abrasive material having arather fine grit size (typically between about 180 and 220 mesh). Thisgrinding wheel 13 is desir-ably annular, and has an inner internallycylindrical opening 70 of a dimension to fit closely about and becarried by a correspondingly cylindrical enlarged diameter portion 71 ofshaft member 55. At one end of surface 71, part 55 integrally carries aradially extending annular flange 72 against which the reduced thicknessportion 73 of wheel 13 abuts axially. At the opposite side of wheel 13,a retaining ring 74 clamps wheel 13 by peening of an annular flange 75on part 55 radially outwardly against an inclined annular surface 76formed along the inner edge of part 74. The wheel 13 may be positivelykeyed against rotation relative to part 55 by means of a pair ofintegral lugs 77 formed on flange 72 and projecting into correspondingrecesses or notches formed in abrasive wheel 13. The actual grindingfaces of wheel 13 take the form of two annular faces 78 and 79, facingin opposite axial directions, and converging axially toward one anotheras they advance radially outwardly.

At the location of grinding wheel 1-3 and housing cover 23, the section21 of the housing is of essentially rectangular configuration, with thecover assembly 23 forming in efiect an upper continuation of thisrectangular shape. More specifically, housing section 21 has a verticalend wall 80 extending transversely of axis 20 and merging with a pair ofparallel vertical front and rear walls 81 and 82 (see Fig. 4). At thelocation of cover assembly 23, these three walls 80, 81 and 82 terminateupwardly in edges 83 which lie in a common horizontal plane, and whichengage and support corresponding lower edges 84 of the main coversection 24. Section 24 has a vertical end wall 85, two vertical frontand rear walls 86 and 87, and a top horizontal wall 88. The walls 85, 86and 87 are aligned vertically with, and form upper continuations of thepreviously mentioned Walls 80, 81 and 82 of housing section 21.Projecting downwardly from each of the three vertical walls 85, 86 and87, part 24 has three integrally formed lugs 89,

which are received at the inner sides of the upper por- -tions of walls80, 81 and 82, and are removably attachable to those walls by threescrews 90 extending through openings in walls 80, 81 and 82 andthreadedly engaged within openings 91 and lugs 89. At a side oppositethe location of end wall 85, part 24 has an edge 92 lying in a verticalplane and engaged against edges formed along the top, front and rear ofpart 21, so that the cover forms a continuation of housing section 21 atthat location. At their upper edges, walls 85, 86 and 87 may curveinwardly smoothly at 93 to merge with the horizontally extending upperwall 88 of part 24.

The walls 86, 87 and 88 of part 24 are interrupted at the location ofsection 25, which forms in effect continuations of walls 86, 87 and 88respectively, but with the previously mentioned knife blade receivingslots 14 and 5 15 being formed between sections 24 and 25 for guiding aknife during a sharpening operation. More specifically, section 25 has asmall vertically extending and then horizontally curving front wallportion 94 which is aligned laterally with front wall 86 of part 24, andsimilarly part 25 has a rear vertical wall 85 aligned laterally with andin the same plane as rear wall 87 of part 24. Across its upper side,part 25 has a top horizontal wall 95 which is aligned horizontally withand forms in effect a continuation of top wall 88 of part 24.

As seen in the plan view of Fig. 3, the slots 14 and 15 converge as theyextend from front to rear, with the angle formed between one of theseslots and axis 20 being the same as but the reverse of the angle formedbetween the other slot and that axis. Also, the portions of the slots 14and 15 which are formed between the vertically extending front walls 86and 94 of sections 24 and 25, and the vertically extending rear walls 87and 195 of sections 24 and 25, converge downwardly, so that a bladereceived within either the slot 14 or the slot 15 is inclined downwardlyand inwardly toward grinding wheel 13, as well as being disposed at anangle with respect to its front to rear extent. Section 24 has twoinclined and angularly extending walls 96 and 97 formed within thehousing beneath the level of the upper walls 88 and 96, and extendingall of the way from front wall 86 to rear wall 87. These walls 96 and 97are disposed at an angle corresponding to the angle of the bladereceived within and guided by slots 14 and 15 respectively, to thuslaterally support the blade as it is drawn forwardly through the slotswhile engaging the grinding wheel 13. The peripheries of inclined planarwalls 96 and 97 form first sides of the knife guiding slots 14 and 15,with the opposite sides of those slots being formed by opposed edges ofpart 25, which edges extend parallel to and in spaced relation to theedges of surfaces 96 and 97. Thus, the various edges forming slot 14,and the associated guide surface 96, are positioned to receive and guidea planar knife blade within slot 14 and against surface 96, and the sameis true of slot 15 and the associated surface 97. Walls 96 and 97 may beinterrupted toward their forward ends at 98, sufficiently to allow forreception of the wheel 13 between these walls 96 and 97 without anyinterference being offered by the walls. At the bottom of the recessformed in part 24 by the downwardly extending walls 96 and 97, the part24 has a horizontal bottom wall 99, which is spaced a short distanceabove edges 83 and 84, and also above axis 20 of wheel 13, and whichacts to support the engaged knife blade in a horizontally extendingposition, and to limit the downward movement of the knife blade. At theforward side of wheel 13, there may be provided a short forwardcontinuation 100 of horizontal wall 99, to engage the blade at thatlocation.

As the knife blade 102 received within slot 14 or 15 is pulled forwardlywithin that slot, the cutting edge 101 of the blade (see Fig. 4) engagesone of the two grinding faces 78 or 79 of grinding wheel 13, at theforward side of the grinding wheel, so that the knife may be sharpenedon both of its sides by first pulling it forwardly through slot 14, andthen pulling it forwardly through slot 15. The grinding wheel 13 turnsin a direction such that the forward engaged portion of the grindingwheel is moving upwardly, to thus perform a most effective sharpeningoperation. Also, as will be apparent, the angularity of annular grindingfaces 78 and 79 with respect to the axis of wheel 13 is such as tocorrespond with the angularity of the knife blade at the point ofengagement of the blade with the grinding wheel, so that surface 78 or79 engages the knife blade across the entire radial extent of face 73 or79.

In order that the part 25 may form the inner edges of the two convergingknife guiding slots 14 and 15, this part 25 has opposite side edges 103and 104, which converge rearwardly along the top of the housing. andWhich converge downwardly at the rear and front side of the housing (butwith the edges being spaced farther apart at the rear of the housingthan at its front). All portions of edge 103 of course lie in a commoninclined plane, and similarly all portions of edge 104 lie in a singleplane. Part 25 is mounted in fixed relation to the other cover section24 in any suitable manner, as by means of a screw 105 extending upwardlythrough an opening in horizontal bottom wall 99 of part 24, andthreadedly connected into a threaded bore 106 in a vertically extendingportion 107 of part 25. This attachment may be strengthened by providinga vertical web 103, whose lower edge engages the upper side of wall 99at 109, and which may be cut away arcuately at its forward edge 110 toavoid contact with wheel 13. Also, lugs 111 formed on the upper surfaceof wall 99 may be receivable within locating recesses in the undersideof Web 108, to assist in locating part 25 relative to part 24.

As previously mentioned, the square bushing 62 which journals the outerend of cutter mounting shaft 55 is locked in its operative position byattachment of the cover assembly 23to the upper side of housing part 21.For this purpose, part 24 of the cover assembly may have a pair ofvertically extending and generally parallel webs or walls 112 (see Fig.5) which may extend vertically and perpendicular to end wall 85, andwhose lower extremities contain small essentially right angle recesses113 adapted to engage and confine and positively position the upperportion of bushing 62. More specifically, each of these notches orrecesses has an upper horizontal wall 114 which bears tightly downwardlyagainst the upper horizontal surface of square bushing 62, and each ofthe webs 112 forms also a small lug 115 projecting downwardly along oneside of the bushing 62 in a relation positively holding bushing 62 in afixed position within the housing when cover assembly 23 is held in itsFig. 2 assembled position by screws 90. The bushing is held againstaxial movement axially away from shaft part 55 by means of abuttingengagement of a transverse vertical end surface 116 on.bushing 62 with acorrespondingly vertical and transverse surface formed at the inner sideof wall 85 of part 24. Also, bushing 62 may have a similar engagement atits lower edge with housing part 21 at 117.

To now describe the manner of operation of the illustrated device, whenit is used as a knife sharpening device, assume first that the actuatinghandle 27 is in its upwardly projecting broken line position of Fig. 1.From this position, the handle 27 is swung to its full line position ofFig. 1 and into engagement with actuating element 28 of switch 29, toclose that switch and thus energize motor 16. As shaft 19 of the motorturns, it turns the carried gear 48, which drives gear 50, and which inturn engages and drives the gear portion 54 of the wheel carrying part55. This turns grinding wheel 13 at a relatively fast speed, typically9000 rpm. where motor 16 is a two pole induction motor. The user thencan pull the knife blade 102 forwardly through slot 14 and then throughslot 15, perhaps several times, so that the opposite sides of thecutting edge of the knife can engage the tapering surfaces 78 and 79 ofthe grinding wheel (at a proper angle determined by the angularity ofthe slots and of faces 78 and 79), to thus produce an accuratelypredetermined type of cutting edge on the blade.

When it is desired to remove and replace the grinding wheel 13, after ithas become worn, this may be effected by merely removing cover assembly23 (comprising parts 24 and 25 rigidly secured together), to thus freethe entire grinding unit for easy removal from the housing. Morespecifically, the screws 90 are removed from the device, and then thecover assembly 23 is free to be easily removed upwardly from the rest ofthe housing. This exposes the grinding wheel, so that a user may graspthat wheel and lift it upwardly very slightly to pass the verticalsurface on wall 80 at 117, following which the 7 grinding wheel 13 andits carrying part 55 may be slipped axially out of its position ofengagement with bushing retaining element 63, so that an entirely newgrinding assembly may be substituted. The bushings 62 and 61 are removedwith this assembly which includes parts 55, 13, and 73, so that theentirely new assembly which is substituted will include parts 55, 13,73, 61 and 62. After this assembly has been positioned as shown in Fig.2, the cover assembly 23 may be placed back into its active position, tothus lock bushing 62 and the other parts in their active Fig. 2positions, and the cover may then be positively retained in thatposition by screws 90 so that the entire apparatus will then be againready for use. As the new grinding assembly is slipped into place, it isfirst placed in the position of Fig. 10, and then is slipped axiallyinto a position in which shaft portion 59 and bushing 61 are properlyreceived within element 63, following which bushing 62 may be slippeddownwardly a short distance into its position-of engagement with thevertical wall 117 of part 21, to thus ready the entire apparatus forreceipt of the locking cover assembly.

I claim:

1. A knife sharpening device comprising a housing, an electric motor insaid housing having a rotatably driven shaft, a second shaft removablymounted in an active position in the housing and driven by said firstshaft, a grinding wheel carried by said second shaft for sharpening aknife, said housing including a main section and a removable coversection forming an upper side of the housing at the location of saidgrinding wheel, fastener means for detachably securing said coversection in a predetermined assembled position relative to said mainsection of the housing, said cover section being apertured to allowcontact of said grinding wheel with a knife to sharpen the knife whenthe cover section is insaid assembled position, two removable bushingsextending about and rotatably journalling said second shaft near itsopposite ends respectively and at opposite axial sides of said grindingwheel, a shoulder carried by said main section of the housing and onwhich a first of said bushings is supported in an active positionthereof, a locking shoulder on said cover section adapted to engagedownwardly against said first bushing and coact with said first shoulderin confining and locking said first bushing in its active position whenthe cover is in said assembled position thereof, a boss structure in thehousing removably receiving and positioning the second of said bushings,

said second bushing and said second shaft being removable from said bossstructure only by axial movement relative thereto in a direction towardthe location of said first shoulder, one of said housing sections beingconstructed to block said axial detachment of said second shaft from theboss structure when said cover section is in its assembled position,said second shaft and said wheel and said two bushings being freed foraxial detachment from the boss structure and for complete removal fromthe housing when said cover section is removed from the main section ofthe housing, a first gear rotatably mounted in the housing and driven bysaid motor, and a second gear carried by said second shaft and adaptedto move into and out of meshing driven relation with respect to saidfirst gear by movement of the second shaft into and out of activeposition.

2. A knife sharpening device as recited in claim 1,

in which said first bushing is of essentially rectangular cross section,said main housing section containing an essentially rectangular recessfor receiving a portion of said bushing and having said first shoulderas a bottom Wall of the recess, there being two of said locking'ShOlll-r ders carried by the cover section and formed by two lugscontaining essentially right angle recesses receiving and locating twocorners respectively of said first bushing.

3. A knife sharpening device as recited in claim 1, in which said firstgear is an idler gear mounted in the housing for rotation about an axisparallel to but offset from the axes of said first and second shafts,there being a. third gear carried by said first shaft and driving saididler gear.

4; A knife sharpening device comprising a housing, an electric motor insaid housing having a rotatably driven shaft, a second shaft removablymounted in an active position in the housing and driven by said firstshaft, a grinding wheel carried by said second shaft for sharpening aknife, said housing including a main section and a removable coversection at the location of said grinding wheel, fastening means fordetachably securing said cover section in a predetermined assembledposition relative to said main section of the housing, said coversection being apertured to allow contact of said grinding Wheel with aknife to sharpen the knife when the cover section is in said assembledposition, a bearing rotatably journalling said second shaft near a firstend thereof, locking shoulder means carried by said cover section andadapted by movement of said cover section to said assembled position toclamp said bearing against said main housing section in a predeterminedactive position and to thereby lock said second shaft in its activegrinding position, a boss structure carried by said main housing sectioncarrying means for journalling the second end of said second shaft, saidsecond end being detachable from said boss structure only by axialmovement, one of said body sections being constructed to block saidaxial detachment of the second shaft from the boss structure when saidcover section is in its assembled position, said bearing and said secondshaft and grinding wheel being freed by said locking shoulder means fordetachment from the boss structure and complete removal from the housingwhen the cover section of the housing is detached from the main section,a first gear in the housing driven by said motor, and a second gearcarried by said second shaft and adapted to engage and be driven by saidfirst gear when the shaft is locked in said active position thereof,said second gear being freely movable out of engagement with said firstgear upon removal of the second shaft and grinding wheel from thehousing.

References Cited in the file of this patent UNITED STATES PATENTS

